Shaving method and shaving cutter

ABSTRACT

A shaving method and a shaving cutter for use in carrying out a shaving operation, wherein the cutter and the gear to be processed are rotated in crossed axes relationship and the gear is shaved by one side tooth flank of a plurality of teeth formed on the circumference of the cutter.

United States Patent 1 Mayuzumi et al.

SHAVING METHOD AND SHAVING CUTTER Inventors: Harutaka Mayuzumi,Kawasaki; Motoyuki Shinoda, Hiratsuka; Kosuke Akizuki, Tokyo, all ofJapan Assignee: Isuzu Motors Limited Filed: Mar. 26, 1970 Appl. No.222,835

Foreign Application Priority Data 1 Apr. 3, 1973 [56] References CitedUNITED STATES PATENTS 2,228,966 l/l94l Miller ..29/104 2,274,491 2/1942Mentley ..29/l03 2,682,100 6/1954 Pelphrey ..90/l.65 2,214,225 9/1940Drummond ..29/104 FOREIGN PATENTS OR APPLICATIONS 199,459 9/1958 Austria..29/1.65

Primary Examiner-Harrison L. Hinson Attorney0tto John Munz [5 7 ABSTRACTA shaving method and a shaving cutter for use in carrying out a shavingoperation, wherein the cutter and the gear to be processed are rotatedin crossed axes relationship and the gear is shaved by one side toothflank of a plurality of teeth formed on the circumference of the cutter.

3 Claims, 10 Drawing Figures PATENTED APR 3 I975 SHEET 1 OF .3

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DC.- C

FIG. 4

INVENTORS HARUTAKA MAYUZUMI,

MOTOYUKI SHINODA, KOSUKE AKIZUKI W MTORNEY PATENTEUAPR 3 I975 sum 2 or 3FIGS INVENTORS HARUTAKA MAYUZUMI,

MOTOYUKI SHINODA KOSUKE AKIZUKI mommy PATENTED RB I975 3, 724,046

SHEET 3 OF 3 FIG. 9

FIG. IO

BACKGROUND OF THE INVENTION It has heretofore been proposed to carry outa shaving operation, particularly a conventional method of shavingoperation as shown in FIG. 1 wherein there are provided a cutter Ahaving helical teeth formed with a cutting edge on each flank and a gearB to be shaved, said cutter A and gear B rotating in crossed axesrelationship for a crossed axes angle of a formed at the intersectingpoint of the axial lines of both cutter and gear. Thus the shavingoperation is carried out by rotating both the cutter and gear and bymoving the gear in the axial direction to extend the shaved portion overthe whole width of the teeth. This conventional method of shavingoperation can be carried out only by means of both flanks of a pluralityof teeth formed on the circumference of the cutter, namely, by means ofboth driving and trailing tooth flanks at the same time.

However, the tooth flanks shaved by the driving side tooth flank and thetrailing side tooth flank are different from each other in points ofshaving stock and processed accuracy and consequently the accuracy ofthe shaved tooth flank of the gear has usually been found non-uniform.Moreover, it must be kept in mind that a regrinding procedure of theshaving cutter is one of the most important problems in the industry.Namely, the regrinding of a shaving cutter has heretofore been carriedout by grinding both flanks of each tooth one by one exactly along theinvolute form of the teeth formed on the circumference of the cutter,thus requiring considerable procedures for processing purposes and highprocessed accuracy.

This kind of regrinding process has been found rather expensive underthe present circumstances.

SUMMARY OF THE INVENTION An object of the present invention is toprovide a shaving method whereby it is rendered possible to make uniformthe accuracy of the flanks of the gear teeth thus shaved by this shavingmethod.

Another object of the invention is to provide a shaving cutter suitablefor carrying out the above shaving method.

Still another object of the invention is to provide a shaving cutterwhich is capable of being reground easily after its use. Thus thecharacteristics inherent in the present invention are known such that acutter and a gear to be processed are rotated in crossed axesrelationship and the gear is shavedsuitably wherein the intersectingpoint of the axial lines of the cutter and the gear to be processed ismoved in the axial direction of the cutter, according to the directionof rotation of the cutter so that one flank of tooth flank of aplurality of teeth formed on the circumference of the cutter, namely,only the tooth flank of the driving side or trailing side is used tocarry out shaving the gear and then the processed accuracy of the gearcan be made uniform.

The above objects and other objects and characteristics of the inventionwill become apparent from the following description with reference tothe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing arelationship between a shaving cutter and a gear to be processed in ashaving operation.

FIG. 2 is a side view showing a meshing relationship between a shavingcutter and a gear to be processed according to the present invention.

FIG. 3 is a view illustrative of the shaving method of the presentinvention, showing a moving procedure of the intersecting point of theaxial lines of the cutter and the gear to be processed as shown in FIG.2.

FIG. 4 is an enlarged view of the substantial part of another embodimentof a moving procedure of the intersecting point of the axial lines ofthe cutter and the gear to be processed.

FIG. 5 is a side view of another embodiment of a shaving cutteraccording to the present invention.

FIG. 6 is an enlarged view of the substantial part of a moving procedureof the intersecting point of the axial lines of a cutter and a gear tobe processed using the shaving cutter shown in FIG. 5.

FIGS. 7 and 8 are side views showing other embodiments of a shavingcutter according to the present invention.

FIGS. 9 and 10 are photographic views of the shaving cutter shown inFIG. 2.

DETAILED DESCRIPTION OF THE INVENTION In FIG. 2, reference numeral 1indicates a shaving cutter consisting of two cutter pieces 2 and 3, eachof which is formed with a plurality of teeth 21 and 31 on thecircumference thereof, one end surface of each tooth having cuttingedges 211 and 212 and 311 and 3 12 respectively.

In the drawing, one tooth only is shown on each cutter piece 2 and 3,while all other teeth are omitted for the sake of brevity.

The above mentioned two cutter pieces 2 and 3 have said cutting edges211 and 311 on one side, which are adapted to confront each other andboth cutter pieces 2 and 3 are combined together with the clearance ttherebetween.

The above mentioned cutter 1 and the gear 4 in crossed axes relationshipare rotated so that the gear 4 can be shaved suitably.

At the same time, the gear 4, while rotating with the cutter, is movedin the axial direction whereby the entire width of the gear can beshaved accordingly;

By the way, in the following description, only a tooth on each cutterpiece is explained with reference to its construction and action for thesake of brief explanation, but the same principle will naturally applyas it is in a plurality of teeth formed on each cutter piece. Therefore,the following description must be understood as such concerning allteeth on each cutter piece.

When the cutter 1 and the gear 4 are caused to rotate in crossed axesrelationship and the gear 4 moved in the direction of the arrow L asshown in FIG. 2, namely, when moved to the left as shown in FIG. 3, thegear can be shaved by the cutting edge 211 of the tooth 21 formed on thecircumference of the cutter piece 2. When the gear 4 is moved in thedirection of the arrow R, one-side tooth flank of the gear can be shavedby the cutting edge 31 1 of the tooth 31 formed on the circumference ofthe cutter piece 3. In this shaving operation, the shave-off effectoccurs near the intersecting point of the axial lines of the cutter andthe gear and therefore, as shown in FIG. 3, when the axial position ofthe cutter 1 assumes the line CC and that of the gear to be processedassumes the line DD, the intersecting point of both axial lines showsthe point P and then the gear can be shaved by the cutting edge 211 ofthe tooth 21 formed on the circumference of the cutter piece 2 passingnear the above mentioned intersecting point P. At the same time, sincethe cutting edge 212 of the tooth flank 214 opposite to the tooth flank213 formed with the cutting edge 211 is not positioned near theintersecting point P, no shaving effect occurs on the side of the toothflank 214 but it merely serves to guide the rotating movement of thecutter. At this instant, as shown in FIG. 2, the gear 4 to be processedis moved in the direction of the arrow L, namely, to the left as shownin FIG. 3. When the rotation of the cutter 1 goes on in the direction ofF in this instance, the tooth flank 213 having the tooth 21 formed onthe circumference of the cutter with the cutting edge 211 will play atrailing part and then the shaving operation is carried out by thistrailing tooth flank only.

As is readily apparent from FIG. 3, the end surface between cuttingedges 212 and 211 forms an acute angle with the leading tooth flank 213but forms an obtuse angle with the trailing tooth flank 214. Likewise,the end surface between cutting edges 311 and 312 forms an acute anglewith leading flank 313 and an obtuse angle with trailing flank 314.Flanks 213 and 214 are mutually parallel, as are flanks 313 and 314.

By the way, since the cutter piece 3 is not positioned near theintersecting point P, the cutter does not shave but merely serves toguide its rotation.

According to experimental results obtained by the present inventor,there occurs some extent of shaving effect even by the cutting edges311, 312 and 211 which are not positioned near the above mentionedintersecting point P, and the amount of such shaving effect is extremelysmall so that it gives no bad effect on the processed accuracy of theshaved flank of the gear.

In this way, when one-side tooth flank of the gear is to be shaved andthe gear is moved to the required position in the direction of the arrowL and subsequently, when the gear 4 is moved in the direction of thearrow R, the rotation of the cutter 1 is changed to the direction of thearrow G. At the same time, the gear 4 is moved at right angles to theplane passing through the above mentioned intersecting point P of theaxial lines of the cutter l and the gear so that the axial position ofthe gear 4 is moved from the line DD to the line E--E as shown in FIG. 3and the intersecting point between the cutter 1 and the gear 4 is movedfrom the point P to Q on the axial line of the cutter.

When the intersecting point of the axial lines of the cutter and thegear 4 is moved to the point Q, the remaining part of tooth flank of thegear 4, the initial part of which has already been shaved in the abovementioned first step can be shaved by the cutting edge 311 of the tooth31 formed on the circumference of the cutter piece 3.

Since the rotation of the cutter 1 goes on in the direction of the arrowG as shown in FIG. 3, the tooth flank formed with the cutting edge 311assumes a trailing side so that the shaving operation can be effected bythe trailing tooth flank.

Simultaneously, as the cutting edge 312 of the tooth flank 314 oppositeto the tooth flank 313 formed with the cutting edge 311 on the tooth 31of the cutter piece 3 is not positioned near the intersecting point Q,there occurs no shaving effect on the tooth flank 314 but it merelyserves to guide the rotation of the cutter.

Also at this instant, since the cutter piece 2 is not positioned nearthe intersecting point of the axial lines, there occurs no shavingeffect either but it merely serves to guide the rotation of the cutter.

The disclosure made hereinbefore refers to cases where a shaving effectoccurs at the trailing side of a cutter tooth flank. When carrying out ashaving operation at a driving side of cutter tooth flank, the axialposition of the gear 4 has only to be moved in such a manner that whenthe rotation of the cutter 1 goes on in the direction of the arrow F,the intersecting point of the axial lines of the cutter 1 and the gear 4should come on the point Q and when the rotation of the cutter 1 goes onin the direction of the arrow G, the intersecting point should come onthe point P.

As the procedure of moving the intersecting point of the axial lines ofthe cutter 1 and the gear 4 to the axial direction of the cutter,besides the method of moving the gear as explained with reference toFIG. 3, there is also another method of moving the cutter.

Now such method will be explained in detail with reference to FIG. 4hereinbelow.

When the axial position of the cutter remains on the line CC and that ofthe gear on the line DD respectively, the intersecting point of theaxial lines falls on the point P.

In this case, the first. step consists in moving the cutter to theposition shown by the full line and positioning only the cutting edge211 and the tooth 21 on the circumference of the cutter piece 2 near theintersecting point P of the axial lines of the cutter and the gear. Thesecond step consists in moving the cutter to the position shown by thedotted line on the axial line CC of the cutter and positioning only thecutting edge 311 of the tooth 31 of the other cutter piece 3 near theabovementioned intersecting point P.

Consequently, when the above mentioned cutting edge 211 is positionednear the intersecting point P, the direction of rotation' of the cutteris rendered downward and when the above mentioned cutting edge 311 ispositioned near the intersecting point P, the direction of rotation ofthe cutter is rendered G and thus it is possible to carry out theshaving operation only by the tooth flank of the trailing side.

When carrying out the shaving operation by the tooth flank of thedriving side of the cutter, it is sufficient to make the direction ofrotation of the cutter G when the above mentioned cutting edge 211 ispositioned near the intersecting point of the axial lines and to makethe direction of rotation of the cutter F when the above mentionedcutting edge 311 is positioned near the intersecting point of the axiallines.

In the case of carrying out the shaving operation only by the toothflank of the driving side of the cutter, when the above mentionedcutting edge 211 is positioned near the intersecting point P, thedirection of rotationof the cutter has only to be made G and when theabove mentioned cutting edge 311 is positioned near the intersectingpoint P, the direction of rotation of the cutter has only to be made F.

According to the shaving method of the present invention as mentionedabove, the intersecting point of the axial lines of the cutter and thegear is moved onto the axial line of the cutter, whereby the gear to beprocessed can be shaved by either the tooth flank of the driving side ofthe cutter or that of the trailing side so that the processed flank ofthe shaved gear can be obtained in a uniform manner.

In the shaving cutter for use as explained above, the cutter 1 consistsof two cutter pieces 2 and 3 and moreover, there are provided thecutting edge 211 and 311 on each confronting end of the teeth 21 and 31formed on the circumference of the cutter piece 2 and 3 respectively.

With this arrangement, in the case of regrinding the shaving cutter, itis sufficient to grind each end surface of the cutter pieces 2 and 3.Consequently the operation of regrinding becomes very easy to carry outand what is more, the machining steps are reduced so that regrindingcost is considerably saved, as compared with conventional regrindingtechniques.

- FIG. 5 shows another embodiment of a shaving cutter suitable for usein the shaving method of the present invention. Namely there are formedhelical teeth 6 on the circumference of a cutter piece 5 and a series offirst cutting edges 63 on a first tooth flank 61 respectively from afirst end surface 65 to a point near the middle of the first flank, theremaining section 66 of the first flank being a smooth surface. A seriesof second cutting edges 64 is formed on an opposed second tooth flank 62from an opposed second end surface 67 up to a point near the end of thesecond flank, the remaining section 68 of the second flank being asmooth surface.

An example of use of the shaving cutter will be explained with referenceto FIG. 6.

As shown in FIG. 6, when the axial position of the shaving cutterassumes the line CC and the axial position of the gear to be processedassumes the line D-D respectively, there occurs the intersecting point Pof the axial lines of both cutter and gear, and the shaving operation ofthe gear can be carried out by the cutting edge 64 positioned near theabove mentioned intersecting point.

At the same time, since the tooth flank 62 formed with the cutting edge64 and the cutting edge on the tooth flank 61 are not positioned nearthe intersecting point P of the axial lines of the cutter and the gear,there occurs no shaving effect on them.

I When the direction of rotation of the shaving cutter assumes thedirection of F, the tooth flank formed with the cutting edge 64 becomesa trailing side so that oneside tooth flank of the gear can be shaved bythe tooth flank of the trailing side only.

In this way, when one-side tooth flank of the gear is to be shaved, thedirection of rotation of the shaving cutter is changed to the directionof G and simultaneously, the axial position of the gear is changed tothe position of E-E, then the intersecting point of the axial lines ofthe cutter and the gear is changed to the point Q so that the shavingoperation can be carried out by the cutting edge 63 positioned near theintersecting point Q.

At the same time, however, the tooth flank 61 formed with the cuttingedge 63 and the cutting edge 64 formed on the opposite tooth flank arenot positioned near the intersecting point Q, there occurs no shavingeffect at all. In this case, since the direction of rotation of theshaving cutter is G, the tooth flank 61 formed with the cutting edge 63becomes a trailing side so that it is possible to shave the tooth flankopposite to the area shaved by the above mentioned cutting edge 64 ofthe gear only by the tooth flank of the trailing side.

In shaving cutters of the type are formed a plurality of cutting edges63 and 64 respectively on the tooth flanks 61 and 62 of the tooth 6 sothat a plurality of cutting edges are found to be positioned near theintersecting point of the axial lines of the cutter and gear, thusrendering its shaving efficiency by far better than that of the shavingcutter shown in FIGS. 2 through 4.

FIG. 7 shows another embodiment of shaving cutter according to thepresent invention. It consists of two cutter pieces 7 and 8 and thetooth 71 is formed on the circumference of the cutter piece 7 on oneside and the tooth 81 on the cutter piece 8 on the other side. Of thetooth flanks 711 and 712 of the tooth 71 on the cutter piece 7 on oneside, the tooth flank 712 is formed with the cutting edge 713.

Likewise, of the tooth flanks 811 and 812 on the tooth 81 formed on theother-side cutter piece 8, the tooth flank 81 1 is formed with thecutting edge 813.

As shown in FIG. 7, the above mentioned two cutter pieces 7 and 8 showthat the tooth 71 on the cutter piece 7 and the tooth 81 on the othercutter piece 8 are so constituted to form a tooth in a body andfurthermore, the tooth flank 712 formed with the cutting edge 713 andthe tooth flank 812 formed with the cutting edge 813 respectively arejoined together so as to form mutually opposite tooth flanks and thenthey are combined by fixing means such as bolts and nuts, whereby ashaving cutter can be obtained almostsimilar to that shown in FIGS. 5and 6.

In shaving cutters of this kind are provided two cutter pieces 7 and 8so that it is possible to provide cutting edges all over the entirewidth of the tooth only in the tooth flank of the same direction as thatof the tooth 71 and 81 provided on the cutter pieces 7 and 8respectively and therefore the manufacture of shaving cutters themselvesis rendered easier than that shown in FIGS. 5 and 6. Moreover, since theshaving cutter consists of two cutter pieces, the tooth width of eachpiece may be made small and so it is rendered possible to ensure leastoccurrence of error in the processing of cutter tooth flanks, therebyenabling a shaving cutter with a precise tooth flank to be obtained.

FIG. 8 shows still another embodiment of a shaving cutter according tothe present invention.

This embodiment provides the interposition of a spacer 10 between thetwo cutter pieces 7 and 8 which are shown in FIG. 7 and also theformation of the clearance S therebetween. In a shaving cutter of thistype, the clearance S is provided in the joint portion between the twocutter pieces 7 and 8 so that the shaving cutter can deal with cut dustduring the shaving operation more efficiently than those shown in FIGS.5,

6 and 7, thus ensuring improvements in overall processed accuracy.

What is claimed is:

l. A shaving cutter comprising a plurality of teeth, each tooth having afirst flank and a second flank, the second tooth flank being an oppositeflank to said first tooth flank, and first and second end surfaces, thefirst tooth flank running from said first end surface to said second endsurface and having a series of first cutting edges thereon extendingfrom the first end surface to a point near the middle of the first flankand having a smooth surface over the rest of the first flank, the secondtooth flank running from said first end surface to said second endsurface and having a series of second cutting edges thereon running fromthe second end surface to a point near the middle of the second flankand having a smooth surface over the rest of the second flank.

2. A shaving cutter according to claim 1 wherein the cutter comprisestwo disc-like pieces, each piece having a plurality of tooth portions,the pieces being arranged near each other so that the tooth portions onone of the disc-like pieces are aligned with the tooth portions on theother of the disc-like pieces, the aligned tooth portions forming saidteeth the cutting edge of the first flank of each tooth and the dulledge of the second flank of each tooth being on a first one of thedisc-like pieces and the cutting edge of the second flank of each toothand the dull edge of the first flank of each tooth being on a second oneof the disc-like pieces. I

3. A shaving cutter according to claim 2 wherein said two disc-likepieces are arranged near each other to leave a small clearance gaptherebetween.

1. A shaving cutter comprising a plurality of teeth, each tooth having afirst flank and a second flank, the second tooth flank being an oppositeflank to said first tooth flank, and first and second end surfaces, thefirst tooth flank running from said first end surface to said second endsurface and having a series of first cutting edges thereon extendingfrom the first end surface to a point near the middle of the first flankand having a smooth surface over the rest of the first flank, the secondtooth flank running from said first end surface to said second endsurface and having a series of second cutting edges thereon running fromthe second end surface to a point near the middle of the second flankand having a smooth surface over the rest of the second flank.
 2. Ashaving cutter according to claim 1 wherein the cutter comprises twodisc-like pieces, each piece having a plurality of tooth portions, thepieces being arranged near each other so that the tooth portions on oneof the disc-like pieces are aligned with the tooth portions on the otherof the disc-like pieces, the aligned tooth portions forming said teeththe cutting edge of the first flank of each tooth and the dull edge ofthe second flank of each tooth being on a first one of the disc-likepieces and the cutting edge of the second flank of each tooth and thedull edge of the first flank of each tooth being on a second one of thedisc-like pieces.
 3. A shaving cutter according to claim 2 wherein saidtwo disc-like pieces are arranged near each other to leave a smallclearance gap therebetween.